Electrochromic Smart Windows with On-Demand Photothermal Regulation for Energy-Saving Buildings

Electrochromic smart windows with dynamic photothermal management can enhance living comfort and reduce building energy consumption. However, they usually suffer from low selectivity and optical modulation in visible (VIS) and near-infrared (NIR) regions owing to the coupled mechanism restriction. Here, the reversible deposition and ion adsorption in WO₃//MnO₂-based smart windows are decoupled using a hybrid electrolyte, realizing their independent and efficient VIS-NIR regulation. The Cu²⁺/Mn²⁺ ions in the hybrid electrolyte enhance proton adsorption on the WO₃ surface while impeding proton insertion, imparting state-of-the-art NIR regulation to the WO₃ electrode. Moreover, the synergy of protons and Cu²⁺/Mn²⁺ ions facilitates reversible MnO₂ electrodeposition on the electrode, triggering independent tuning of VIS light with an optical modulation of 94%. The outdoor test and simulation reveal that the smart window achieves cooling at 5-10 °C, an energy savings of 73.2 MJ m^-2 and a reduction of 14.4 kg of CO₂ emissions per square meter of the building annually. This work would contribute to energy-saving and emission-reduction solutions in widespread applications.